<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var arr = new Array();
        arr[0] = 'hi array';
        arr[1] = 12;
        console.log(arr);
        var arr2 = [];
        arr2[0] = 'hello';
        console.log(arr2);
        console.log('len = ' + arr.length);
        for (index, v in arr) {
            console.log(v);
        }
    </script>
</body>
</html>